"The United States is a nation of immigrants, and we should be proud of that," Zuckerberg wrote. "We should also keep our doors open to refugees and those who need help. That's who we are. Had we turned away refugees a few decades ago, Priscilla's family wouldn't be here today."
It's worth noting that Zuckerberg's statement was relatively mild compared to some of the responses Trump's executive order has attracted so far. The American Civil Liberties Union filed a lawsuit Saturday morning challenging Trump's order after two Iraqi men with immigrant visas were barred from entering the United States at John F. Kennedy International Airport.
"President Trump's war on equality is already taking a terrible human toll," Omar Jadwat, director of the ACLU's Immigrants' Rights Project, said in a statement. "This ban cannot be allowed to continue."
Lena F. Masri, national litigation director for the Council on American-Islamic Relations, denounced the executive order as one "based on bigotry, not reality."
House Democratic Leader Nancy Pelosi (Calif.), along with many other Democratic lawmakers, ripped the temporary ban on Friday.
Zuckerberg's statement, meanwhile, struck a conciliatory tone in the middle, perhaps in an effort to salvage an immigration program he has championed. The Facebook founder said he "was glad to hear President Trump say he's going to 'work something out' for Dreamers - immigrants who were brought to this country at a young age by their parents."
Under the Deferred Action for Childhood Arrivals (DACA) program, started by the Obama administration in 2012, so-called "dreamers" are allowed to live and work legally in the United States. Zuckerberg once donated $5 million to a college fund for undocumented immigrants.
"I hope the President and his team keep these protections in place, and over the next few weeks I'll be working with our team at FWD.us to find ways we can help," Zuckerberg wrote, referring to the nonprofit organization started in 2013 by numerous tech luminaries, including himself, to advocate for "common sense immigration reform."
The Verge's Casey Newton reported that many tech executives are finding they must maintain a delicate balance when it comes to being critical of Trump.
"On one hand, they face internal and external pressure to speak out against the administration's erratic policymaking, which a majority of Americans oppose," Newton wrote for the technology news site. "On the other, they are striving to maintain good relations with the government, with which Facebook regularly has business. (Not to mention that Trump's tweets alone have regularly sent companies' stock prices tumbling.)"
Some have speculated that Zuckerberg is ramping up his own bid for the White House in 2020. (Indeed, the top comment on his post Friday is from one follower who wants Zuckerberg to run for president already - though it's unclear how serious he is. "Please make me the executive director of memes when you get elected!" he added.)
Zuckerberg ended his statement on a hopeful note, writing of a class he taught at a local middle school where some of his best students were undocumented.
"They are our future too," Zuckerberg wrote. "We are a nation of immigrants, and we all benefit when the best and brightest from around the world can live, work and contribute here. I hope we find the courage and compassion to bring people together and make this world a better place for everyone."